#include <iostream>
using namespace std;

class Mammal
{
public:
	void move() const{cout << "Mammal move one step!\n";}
	void move(int dis) const{cout<<"move "<< dis << " step.\n\n";}
};

class Dog : public Mammal
{
public:
	void move() const{cout << "Dog move one step \n";}
	int virtual speak(){cout<< "hello"<<endl; return 90;}
};

int main()
{
	Dog dog;
	dog.move();
	dog.Mammal::move(100);
	int s = dog.speak();
	cout << " s is " << s << endl;
	return 0;
}